Antifouling compositions and processes for using them

ABSTRACT

A process for inhibiting fouling in chemical processing and oil refining equipment used to process and refine petroleum derived stock material comprising incorporating into said material an antifouling admixture comprising: 1. A major amount of an oil-soluble basic amino nitrogencontaining addition methacrylate-type of polymer, 2. A minor amount of at least one Schiff&#39;&#39;s base condensate derived from condensing hydroxylated aromatic aldehyde with aliphatic amines containing two to six carbon atoms, and 3. A minor amount of at least one diarylamine.

baited States Patent Hubbard ANTIIFOULHNG COMPOSITIONS AND PROCESSES FOR USING THEM [75] Inventor: James Nathan Hubbard, Nederland,

Tex.

[7131 Assignee: Texaco Inc., New York, NY.

[22] Filed: Oct. 27, 1970 [21] Appl. No.: 84,472

[52] US. Cl. 208/48 AA, 252/68, 252/403 [51] HnLCI. C10g9/16,C10t 1/14 [58] Field of Search 208/48 AA [56] References Cited UNITED STATES PATENTS 3,390,073 6/1968 Godar et al. 208/48 AA 3,554,897 l/1971 Stanley 208/48 AA 3,062,744 11/1962 Thompson 252/51.5 3,574,088 4/1971 Bsharah et a1. 208/48 AA 3,546,097 12/1970 Tupper 208/48 AA Primary Examiner-Delbert E. Gantz Assistant ExaminerG. E. Schmitkons Attorney-Thomas H. Whaley and Carl G. Ries [57] ABSTRACT polymer, 2. A minor amount of at least one Schiffs base condensate derived from condensing hydroxylated aromatic aldehyde with aliphatic amines containing two to six carbon atoms, and 3. A minor amount of at least one diarylamine.

11 Claims, No Drawings ANTII OUIJING COMPOSITIONS AND PROCESSES FOR USING 'IIIlElVI This invention concerns compositions and processes for extending the operational life of chemical processing equipment.

More particularly this invention relates to novel compositions useful as fouling inhibitors in the processing and treatment of petroleum derived products.

The economics of high temperature chemical processing, particularly continuous processing, require uninterrupted and extended periods of operation to be profitable. Not only is start-up time consuming and disproportionately expensive but unplanned repair and maintenance work are disruptive in achieving production schedules.

In the refining and processing of petroleum products many of the surfaces of operating units come into frequent contact with crude and corrosive materials at temperatures ranging between 200 and l,200 F. and higher and eventually become coated with deposits of oil-soluble materials. This is particularly a problem in the case of equipment such as reactors, heat exchangers, pumps, distillation columns, boilers, catalytic crackers and the like. The built up deposits of the fouling material function as an insulating material and cause problems such as:

1. decreased heat transfer,

2. costly overfiring to compensate for heat transfer losses,

3. expensive and frequent periods of down time to remove fouling deposits from coated parts,

4. reduced or lost production.

In petroleum refining operations, the nature of the fouling deposits varies according to the type of operation conducted, the purity of the petroleum derived material and the mechanism by which the deposition is formed. Experience within the petrolum industry has shown that the oil-insoluble fouling deposits fall within four main categories:

a. high molecular weight hydrocarbon polymers,

b. trace metals, particularly heavy metals and metals of the iron group,

c. organic perioxides, and

d. inorganic salts.

In view of the considerable divergence in the possible type of foulants encountered, until recently most antifouling compositions required the presence of several components to be effective. What has been sought are relatively simple and inexpensive, antifouling compositions which, at low concentration levels, would stabilize incipient polymer-forming hydrocarbons during storage and use, which would be capable of dispersing and which are capable of inhibiting fouling materials already formed to prevent their agglomeration so that they remain suspended in the streams rather than form deposits upon the metal surfaces such as heat exchangers and the like. Desirably, these antifoulants would inhibit fouling in the full spectrum of petroleum materials ranging from crude oils through the various light, intermediate and heavy hydrocarbon distillates including lubricating distillates, gas/oils, kerosenes and the like. Antifoulant compositions possessing this unusual combination of properties would represent a useful advance in the art.

It is an object of this invention among others to provide antifouling compositions useful in the inhibition of the fouling deposits in high temperature processing and refining operations, particularly in equipment having heat exchange surfaces.

It is a more specific object of this invention to provide fouling inhibition in a wide variety of petroleum refining operations ranging from the treatment of crudes to lube oils, gas oils and various other distillates.

Another object of this invention is the development of a multicomponent antifoulant composition whose total antifouling activity is substantially greater than the sum of the activities of the individual components used alone. i

A more specific object is to provide an antifouling composition which can substantially extend the operational life of processing, refining and/or storage equipment coming in contact with hydrocarbon stocks or streams at elevated temperatures.

Additional objects will suggest themselves to those skilled in the art after a further reading of this application.

In practice, a material ultimately derived from petroleum treating or refining operations is treated with a composition defined below, using treatment methods of the art until an antifouling amount is present in the material. The material which then can be refined or processed in the usual manner willl then provide a substantial inhibition of fouling compared to the untreated petroleum material.

The multicomponent compositions of this invention consist of as essential components:

1. A major amount of an oil-soluble, basic amino nitrogen-containing methacrylate addition type of polymer* The use of these polymers as single component antifoulants is disclosed and claimed in coassigned Stanley US. Pat. No. 3,554,897.)

2. A minor amount of at least one Schiffs base condensate derived from condensing a hydroxylated aromatic aldehyde with aliphatic polyamines containing two to six carbon atoms and 3. A minor amount of at least one diarylamine.

In the preferred practice a hydrocarbon liquid to be treated is contacted with from about 7 to 35 parts per million (2 to l0 pounds per thousand barrels) of an admixture of:

l. A metli'acrylic co-, ter-, or tetrapolymer containing basic amino nitrogen atoms, prepared by polymerizing at least one amine-free, polymerizable ethylenically unsaturated alkyl methacrylate monomeric component with at least one basic amino containing dialkylaminoalkyl methacrylate component, the ratio of the alkyl methacrylate monomer to allcylaminoalkyl methacrylate monomer in the polymer ranges from about 10:1 to 25:1 and 2. At least on Schiffs base aliphatic-polyamine condensate selected from the group consisting of N,N'- disalicylidene, alkane diamines and their mixtures, wherein said alkane moiety contains two to six carbon atoms, and

3. At least one diarylamine selected from the group consisting of diphenylamine, phenyl-a-naphthylamine and mixtures thereof, said ratio of the methacrylic polymer to the total nitrogen containing additives ranging from about 1:1 to about 1011.

To more clearly set forth the salient details of this in vention, the following additional description is submitted:

I. Antifouling Composition A. Oil soluble basic amino nitrogen addition type of polymer. These polymers when prepared as described in U.S. Pat. No. 2,737,452 are addition-type polymers containing a plurality of polymerizable ethylenically unsaturated components, at least one of which is amine-free and desirably contains from about eight to 18 carbon atoms in an aliphatic hydrocarbon chain, which, though in the polymer, is not part of the main polymer chain, desirably is predominantly straight chain in nature, and another ethylenically unsaturate monomeric compound, which, as it exists in the polymer, is amine-containing and located in the side chain, said polymer most desirably contains from about 0.1' percent to about 3.5 percent by weight of said additiontype polymer as basic amino nitrogen.

The preparation of these polymers, as disclosed in U.S. Pat. No. 2,737,452 (which also discloses their use as fuel oil stabilizers), is accomplished by polymerizing as completely as possible by conventional bulk, solution or dispersion polymerization, using known initiators or catalysts, admixtures of monomeric components comprising at least one amine-free, unsaturated monomeric component of the alkyl methacrylate type, most favorably those containing from about eight to 18 carbon atoms, and at least one basic amino nitrogencontaining monomeric component of the alkylamino alkyl type, wherein the alkyl groups of the most useful alkylaminoalkyl components contain from one to six carbon atoms.

The preferred oil-soluble basic amino nitrogen addition type of polymers are those selected from the group consisting of co-, terand tetrapolymers containing in polymerized form at least one amine-free, polymerizable ethylenically unsaturated alkyl methacrylate monomer-containing from about four to about 18- carbon atoms and at least one basic amino containing dialkylaminoalkyl methacrylate monomer, wherein the alkyl moieties contain from one to six carbon atoms and the ratio of said alkylmethacrylate to said dialkylaminoalkyl methacrylate 'monomer ranges from about 1011 to about 25:1, said alkylmethacrylate polymer containing from about 0.1 percent to about 3.5 percent by weight of basic amino nitrogen. Illustrative amine free monomers which can be used include the alkyl methacrylates, such as butyl methacrylates, pentyl methacrylates, hexyl methacrylates, heptyl methacrylates, octyl methacrylates, decyl methacrylates, stearyl methacrylate, lauryl methacrylate as well as their mixtures.

Methacrylic monomers containing basic amine nitrogen-containing components which can be used include diethyl aminopropyl methacrylate, dimethylaminoethyl methacrylate, the propylaminoethyl methacrylates and the butylaminobutyl methacrylates as well as their aromatic counterparts. The latter includes phenylarninomethyl methacrylate and tosylaminoethyl methacrylate.

Illustrative useful oil soluble methacrylate polymers include copolymers such as. n-octyl methacrylatediethylaminoethyl methacrylate, decyl methacrylatediethylaminoethyl methyacrylate, ethyl methacrylatediethylamino-methacrylate, la'uryl methacrylatediethylaminoethyl methacrylate, tridecyl methacrylatedimethylaminoethyl methacrylate and the like, terpolymers such as lauryl methacrylate-methacrylanilidediethylaminoethyl methacrylate, decyl methacrylatemethacrylanilide-diethylaminoethyl methacrylate, and

sation of aromatic aldehydes, particularly those con-' taining active hydroxyl groups with aliphatic polyamines, and

2. Diarylamines.

A listing of illustrative aldehydes and polyamines follows.

AROMATIC ALDEHYDES Z-methylbenzaldehyde,

4-methylbenzaldehyde, methoxybenzaldehyde, d-methoxybenzaldehyde, a -naphthaldehyde, a napthaldehyde, 2- hydroxyberizaldehyde (salicylaldehyde), 2-hydroxy-6- methyl benzaldehyde, 2-hydroxy-3- methoxybe'nzaldehyde and the like.

ALIPHATIC POLYAMINES Ethylenediamine, 1,2-propylenediamine, 1,3- propylenediamine, l,6-hexamethylenediamine, 1,10- decamethylenediamine, diethylenetriamine, triethylenetetramine, pentaerythrityltetramine and the like.

ILLUSTRATIVE DIARYLAMINES These amines comprise compounds which contain at least one amino group attached to at least one aromatic radical. Illustrative compounds include among others, diphenylamine, phenyl -a-naphthylamine as well as mixtures of these amines.

II Preferred Antifouling Compositions While all of the previously described combinations of 3-'methyl- 2- Benzaldehyde, benzaldehyde,

. oil'soluble polymers and nitrogen-containing additives function"satisfactorily as antifoulants, as is the case in any large group certain individual members of the group function more effectively than the group at large and are therefore preferred. in this instance the following two methacrylate tetrapolymers used in the indicated proportions in conjunction with the specific Schiffs base condensate of salicylaldehyde and the lower polyamines such as ethylene and propylenediamine and diphenylamine represent the preferred compositions.

That is, five to one parts by weight of tetrapolymer selected from the group consisting of (a) the tetrapolymer of butyl methacrylate-lauryl methacrylatestearyl methacrylate-dimethylaminoethyl methacrylate, and (b) butyl methacrylate-isodecyl methacrylatestearyl methacrylate and dimethylaminoethyl methacrylate, combined with 1 part by weight of N,N'disalicylidene 1,2-propane diarnine and 2 parts by weight of diphenylamine.

lll Feedstocks which can be treated:

The inventive antifoulants can be employed in crude petrolum streams as well as in the treatment of components of products derived from crude petroleum. These include light distillates such as light naphthas, intermediate naphthas, heavy naphthas, middle distillates such as kerosene, gas oil, distillate lube stocks, for example, white oil, saturating oil, light lubes, medium lubes and heavy lubes. Further petroleum substrates include refined hydrocarbons such as xylene, benzene, etc., and, in some instances in the processing of nonhydrocarbons such as alcohols, phenols, etc.

IV Concentration of antifoulant used and method of treating The amount of antifouling agent required for effective inhibition is a variable dependent upon the source of the petroleum substrate treated, e.g., a sour crude or a highly refined xylene, the temperatures and pressures employed as well as the components of the antifouling compositions used. In general, where a particular petroleum substrate has not been treated before, it is beneficial at first to use relatively high treatment levels of the antifouling compositions diluted in a suitable compatible solvent or solvents and then to reduce the treatment level to the point where fouling is barely eliminated. A convenient mode of expressing the concentrations required is in the form of a range either expressed as parts by million of stock treated (P.P.M.) or on the basis of pounds of composition added per thousand barrels of stock (P.T.B.). Satisfactory inhibition of fouling in most feedstock streams can be obtained under practically all conditions encountered between about 1 to 50 pounds of antifoulant per thousand barrels of stock, or about 3.5 to 175 P.P.M. when expressed in parts per million. Lower concentrations tend toward erratic results and higher concentrations are limited by cost. A narrow concentration range of from about 2 to PTB (7-35 PPM.) is more usually employed.

The ratio of oil soluble polymer to nitrogen containing additive ranges between 1:1 to about 10:1. The above concentrations and ratios are herein referred to as an antifouling or inhibiting amount of antifoulant.

No special method of treating the feedstock is required. The components can be applied individually or as an admixture. Compatible solvents may be a convenience in handling the relatively small quantities of material but the antifoulants can be added directly without dilution. The antifouling compositions can be applied batchwise or continuously. In the latter instance a proportioning pump or comparable device may be used to inject the compositions into the stream being treated. V Evaluation of fouling Two general methods are employed, actual refinery use or simulated use. In the plant trials the length of time that a given unit can be operated without the need for defouling maintenance is noted and compared to the average run of a comparable unit untreated. Also noted are the heat transfer values of the unit toward the end of an operating cycle.

In the simulated plant trials the procedure designated as the CFR Coker Test is employed. In this ASTM procedure (ASTM D4660), the tendency of a treated stock material to deposit a fouling coating in a preheater or heat exchanger tube at an elevated temperature is noted and compared to the behavior of an untreated stock under the same conditions. For example, in actual practice the filtered stock under test is charged at a 6 lbs. per hour flow rate over an electrically heated preheater tube which heats the test fraction to a specified temperature, usually about 425 F.

From the preheater section the sample is passed thru a sintered, stainless steel filter, electrically heated to about 500 F. The test is conducted for 300 minutes or until the pressure drop across the filter reaches 25.0 inches of mercury. The latter occurs when a substantial quantity of oil insoluble material clogs the filter and causes the pressure drop to the arbitrarily chosen 25.0 inches limit.

The antifoulant activity of each additive was rated on the basis of its effectiveness to:

1. Inhibit the buildup of deposits on the coker preheater tube compared to the base stock, and

2. Prevent the agglomeration of oil insoluble fouling products which would otherwise precipitate from the sample and become trapped by the cokers filter, resulting in the pressure drop to 25.0 inches of mercury.

The following embodiments and examples are submitted to further aid in the understanding of this invention. Unless otherwise specified all percentages and parts are understood to be by weight rather than volume.

EMBODIMENT A PREPARATION OF A PREFERRED METHACRYLIC POLYMER To a reaction kettle equipped with a means of providing stirring, heating, cooling inert atmosphere is added 4,200 parts by weight of butyl methacrylate and 22 parts by weight of azobisisobutyronitrile. The mixture is stirred until dissolved and 800 parts by weight of dimethylaminoethyl methacrylate, 10,600 parts by weight of lauryl methacrylate and 4,400 parts by weight stearyl methacrylate are added with stirring. At this time 28,600 parts by weight of refined paraffin distillate (150 SU viscosity at 100 F.) is added to the mixture and the reaction mixture is purged with nitrogen gas while stirring for about one-half hour. Then a nitrogen atmosphere (blanket) is maintained over the reaction mixture and the reaction mixture is heated at about C. until a constant value in the refractive index indicates that the polymerization reaction is near completion. At this time an additional 4 parts by weight of azobisisobutyronitrile in benzene is added dropwise to assure that all monomer is polymerized. After an additional 20 minutes of heating and stirring at 85 C. the temperature is raised to C. and kept there until the refractive index shows the reaction is complete.

EMBODIMENT B PREPARATION OF ANOTHER PREFERRED METHACRYLIC POLYMER In this Embodiment the same precedure used to prepare the methacrylic polymer of Embodiment A is followed, the only difference being in the use of isodecyl methacrylate instead of lauryl methacrylate. The same catalyst is employed. The quantities (by weight) of the 4- monomers that are used appear below:

Parts by Wt. Monomer 21 of butyl methacrylate 40 of stearyl. methacrylate 4 of dimethylaminoethyl methacrylate 35 of isodecyl methacrylate After dissolution, purging and heating in a nitrogen atmosphere, and adding additional catalyst to assure the completion of the polymerization reaction, the mixture is heated to 100C and kept there until the refractive index indicates the polymerization is complete.

EMBODIMENT C PREPARATION OF N,N-DISALICYLIDENE-l,2-PROPANEDIAMINE FROM THE CONDENSATION OF SALICYLALDEHYDE AND PROPYLENE DIAMINE EMBODIMENT D PREPARATION OF A PREFERRED AROMATIC AMIDE, p-AMINODIPHENYLAMINE DIOCTANOATE To a reaction vessel equipped with a reflux condenser, heating and stirring means are added at room temperature, 122 parts by weight of paminodiphenylamine, 219 parts by weight of octanoyl chloride and 450 parts by weight of toluene. The reaction mixture is gradually heated to reflux and begins to evolve hydrogen chloride at about 90C. The reaction mixture is refluxed for 4 hours then percolated through silica gel. At this time volatiles are stripped off leaving a yellow to amber oil which slowly crystallizes to a yellow glassy solid. Elemental analysis confirms that the desired amide is present. I

nents of the anti-fouling composition is evaluated in the previously described CFR Coker Test to seemingly comparable multi-component antifouling compositions at comparable concentration.

The base kerosene charge stocks employed have the following properties:

Stock Stock Stock TESTS 7673K 2549Y 5249K Gravity, API 42.5 42.4 42.6 Color, Saybolt +22 +27 +18 Color, Stability, 24 hours. at 220F. +21 +16 Sulfur, wt. X-ray 0.081 0.091 0.059 Gum, Existent, mg./l00 ml 1.0 1.0 1.0 Gum, Potential, mgJlOO ml 1.0 4.0 Nitrogen, Basic, ppm 3.6 l 8 4.0 Nitrogen, Total, ppm 6.0 4.8 Organic Acidity, mg. KOH/g 0.04 0.05 0.09 Copper Content,PPB 106 49 Aromatics/ Olefins 16.1/1.1 14.9/O.7 Water Separometer Index Modified 99 98 94 The flow rate of the filtered charge is 6 lbs. per hour over the preheater tube electrically heated to 425F. and the filter heated to 500F. The heated sample passes from the preheater section through the filter. the test was run for 300 minutes or until a drop of 25.0 inches of mercury is obtained, whichever comes first. A minimal drop in pressure (AP) during the 300 minutes of the run coupled with little or no deposition on the heater tube indicates that antifoulant has superior activity. The results are given in Table l which follows:

TABLE 1 Total Times in additive minutes concenrequired tration lnches to clog Description of Run number and charge stock (ptb) of Hg filter deposits 1. 7673K alone None 25 130 Very small. 2. 2549K alone... None 25 145 Do. 3. 5249K alone None 25 148 Moderate. 4. $249K+ tetrapolymer of A" 2.0 0.2 300 Do. 5. 5249K+tetrapolymer of "A" 5.0 .l 300 Do. 6. $249K+N,N-disalicylidene-l, 5.0 25 149 Small.

2-propane diamine of C". 7. S249K-l-t -amino diphenylamine 5.0 25.0 100 Do.

dioctanoate of D. g 8. K-7673 diphenylamine 5.0 25 62 Trace. 9. K-7673 phenyl-a-naphthyl- 5.0 6 300 Very small.

amine. l0. 7673K+tetrapolymer of A 5.0 0 300 None to trace.

combined with N,N disallcylidene 1,2propane diamine of C (4 ptb) and diphenylamine (1 5th). 11. 2549-y+tetrapolymer of A 5.0 .8 300 Very small to combined with N,N '-disalismall.

cylidene l2,-propane diamine (4 ptb) and p-amino diphenylamine dioctanoate of D (1 ptb).

As can be seen by. the data presented in Table 1, three different batches of kerosene charge stock (runs 1 to 3) used as controls, clogged up the fllter to the extent that a 25 inches drop in mercury pressure is obtained in only 13.0 to minutes although only small deposits of foulants are deposited upon the preheater tube. Runs 4 and 5 show that kerosene solutions of the preferred tetrapolymer at the 2PTB and SPTB level while running the full 300 minutes did cause pressure Similarly, kerosene solutions of the N,N-disalicylidene-l,2-propane diamine (run 6) of paminodiphenylamino dioctanoate (run 7) and of diphenylamine (run 8) even at the SPTB level clog up the filter when used alone in times ranging from 62 to 100 minutes. However, deposits range from traces to small quantities. A SPTB dosage of kerosene solution of phenyl-wnaphthylamine used alone ran the full 300 minutes but gave slightly greater depositions of foulant.

However, the synergistic antifouling effect of the multicomponent compositions disclosed in Tupper US. Pat. No. 3,546,097 (which is believed to be the closest prior art) shown in run ll wherein the tetrapolymer, N,Ndisalicylidene-l,2-propane diamine and p-aminodiphenylamine dioctanoate are used as an antifoulant lnixture is substantially surpassed by the seemingly comparable multicomponent composition of run 10 wherein the sole difference over run 11 is the substitution of diphenylamine for the amide, p-aminodiphenylamine dioctanoate.

Comparable, though somewhat lesser improvements over run ll are obtained under the same tests on the CPR Coker Test when IPTB of phenyl-otnaphthylamine, and p-tertiary octylphenybct naphthylamine are separately substituted for the diphenylamine of run 10.

Similarly, anti-fouling activity comparable to that obtained in run 10 when an equal weight of N,N- disalicylidene, 1,2-ethane diamine is substituted for N,N-disalicylidene, 1,2-propane diamine used in the original run (10).

Various changes, modifications and substitutions can be made in the reactants, reaction conditions and the like without departing from the inventive concept. The metes and bounds of this invention are best determined by the claims, which follow, taken in conjunction with the specification.

What is claimed is:

11. A process for inhibiting fouling in petroleum refining and chemical processing equipment used to process and refine petroleum derived stock material, comprising the steps of treating said petroleum derived stock material with an antifouling amount of an antifouling composition comprising:

a. Major amount of an oil-soluble basic nitrogencontaining methacrylate-type polymer selected from the group consisting of Co-, ter-, and tetrapolymers containing a plurality of polymerizable ethylenically unsaturated components, at least one component which is amine-free and contains from about eight to 18 carbon atoms in an aliphatic chain which though in the polymer is not part of the polymer chain and at least one other ethylenically unsaturated component which as it exists in the polymer is an amine-containing dialkylaminoalkyl methacrylate monomer which is located in the said chain, said polymer containing from about 0.] percent to about 3.5 percent of its weight as basic amino nitrogen, and

b. "A minor amount of at least one nitrogencontaining Schiffs base condensate derived from condensing a hydroxylated aromatic aldehyde with polyamines containing about two to six carbon atoms, and

c. A minor amount of at least one diarylamine selected from the group consisting of diphenylamine, phenyl-a-naphthylamine, p-amino-dipl1enylamine,

p-tertiary octylphenyl-a-naphthylamine and mixtures thereof.

2. The process of claim 1 wherein the hydroxylated aldehyde is salicylaldehyde.

3. The process of claim 2 wherein the petroleum derived stock material is a crude oil.

4. The process of claim 2 wherein the petroleum derived stock material is a gas oil.

5. The process of claim 2 wherein the petroleum derived stock material is a kerosene distillate.

6. A process for inhibiting fouling in chemical processing equipment used to process and refine petroleum derived stock material, comprising treating said material prior to the completion of processing and/or refining with an anti-fouling amount of a composition containing:

a. A major amount of an oil-soluble basic amino nitrogen addition methacrylate-type of polymers selected from the group consisting of co-, ter, and tetrapolymers containing in polymerized form at least one amine-free polymerizable ethylenically unsaturated alkylmethacrylate monomer containing from about four to about 18 carbon atoms and at least one basic amino-containing dialkylaminoalkyl methacrylate monomer, wherein the alkyl moieties contain from one to six carbon atoms, and the ratio of said alkylmethacylate monomer to said dialkylaminoalkyl methacrylate monomer ranges from about 10:1 to about 25:], said methacrylate polymer containing from about 0. 1 percent to about 3.5 percent by weight of basic amino nitrogen,

b. A minor amount of a Schifffs base condensate se lected from the group consisting of N,Ndisalicylidene, 1,2-propane diamine, N,N-disalicylidene, 1,2-ethane diamine and mixtures thereof, and

c. A minor amount of diarylamine selected from the group consisting of diphenylamine, phenyl-oznaphthylamine, p-tertiary-octylphenyl-anaphthylamine, p-aminodiphenylamine and mixtures thereof.

7. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a copolymer.

b. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a terpolymer.

9. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a tetrapolymer.

110. The process of claim 9 wherein the tetrapolymer comprises butyl methacrylate, lauryl methacrylate, stearyl methacrylate and dimethylaminoethylacrylate, the Schiffs base condensate is N,N'-disalicylidene-l ,2- propane diamine and the diarylamine is diphenylamine.

lil. An antifouling composition suitable for inhibiting the fouling of petroleum derived stock material comprising:

a. from about 10 to 1 parts by weight of an oil soluble, basic amino nitrogen alkyl methacrylate tetrapolymer comprising prior to polymerization:

i. at least one amino-free polymerizable monomer containing eight to 18 carbon atoms, and

ii. at least one basic amino-containing dialkylaminoalkyl methacrylate, monomer wherein the alkyl moiety contains one to six carbon atoms,

b. a minor amount of diphenylamine, and

c. a minor amount of N,N-disalicylidene-1,2- 

1. A MAJOR AMOUNT OF AN OIL-SOLUBLE BASIC AMINO NITROGENCONTAINING ADDITION METHACRYLATE-TYPE OF POLYMER,
 2. A MINOR AMOUNT OF AT LEAST ONE SCHIFF''S BASE CONDENSATE DERIVED FROM CONDENSING HYDROXYLATED AROMATIC ALDEHYDE WITH ALIPHATIC AMINES CONTAINING TWO TO SIX CARBON ATOMS, AND
 2. The process of claim 1 wherein the hydroxylated aldehyde is salicylaldehyde.
 3. The process of claim 2 wherein the petroleum derived stock material is a crude oil.
 3. A MINOR AMOUNT OF AT LEAST ONE DIARYLAMINE.
 4. The process of claim 2 wherein the petroleum derived stock material is a gas oil.
 5. The process of claim 2 wherein the petroleum derived stock material is a kerosene distillate.
 6. A process for inhibiting fouling in chemical processing equipment used to process and refine petroleum derived stock material, comprising treating said material prior to the completion of processing and/or refining with an anti-fouling amount of a composition containing: a. A major amount of an oil-soluble basic amino nitrogen addition methacrylate-type of polymers selected from the group consisting of co-, ter, and tetrapolymers containing in polymerized form at least one amine-free polymerizable ethylenically unsaturated alkylmethacrylate monomer containing from about four to about 18 carbon atoms and at least one basic amino-containing dialkylaminoalkyl methacrylate monomer, wherein the alkyl moieties contain from one to six carbon atoms, and the ratio of said alkylmethacylate monomer to said dialkylaminoalkyl methacrylate monomer ranges from about 10:1 to about 25:1, said methacrylate polymer containing from about 0.1 percent to about 3.5 percent by weight of basic amino nitrogen, b. A minor amount of a Schifff''s base condensate selected from the group consisting of N,N''disalicylidene, 1,2-propane diamine, N,N-disalicylidene, 1,2-ethane diamine and mixtures thereof, and c. A minor amount of diarylamine selected from the group consisting of diphenylamine, phenyl- Alpha -naphthylamine, p-tertiary-octylphenyl- Alpha -naphthylamine, p-aminodiphenylamine and mixtures thereof.
 7. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a copolymer.
 8. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a terpolymer.
 9. The process of claim 6 wherein the addition-type, methacrylate-type polymer is a tetrapolymer.
 10. The process of claim 9 wherein the tetrapolymer comprises butyl methacrylate, lauryl methacrylate, stearyl methacrylate and dimethylaminoethylacrylate, the Schiff''s base condensate is N,N''-disalicylidene-1,2-propane diamine and the diarylamine is diphenylamine.
 11. An antifouling composition suitable for inhibiting the fouling of petroleum derived stock material comprising: a. from about 10 to 1 parts by weight of an oil soluble, basic amino nitrogen alkyl methacrylate tetrapolymer comprising prior to polymerization: i. at least one amino-free polymerizable monomer containing eight to 18 carbon atoms, and ii. at least one basic amino-containing dialkylaminoalkyl methacrylate, monomer wherein the alkyl moiety contains one to six carbon atoms, b. a minor amount of diphenylamine, and c. a minor amount of N,N''-disalicylidene-1,2-propane diamine. 